In "solid color pattern" knitting machines, it is the usual practice to continuously feed both the active and inactive pattern yarns throughout the knitting cycle of each sock. These continuously fed pattern yarns extend in a twisted cordlike yarn bundle throughout each sock and from one sock to the next sock. The twisted cord bundle must be cut between the socks as they are removed from the knitting machine and the yarn ends inside of each stocking must be cut to remove the twisted together pattern yarns. In some cases, the yarns forming the cord may become entangled or pulled and produce faulty knitting, thereby resulting in defective socks. Also, the yarn loss resulting from the interconnection and the continuous feeding of the pattern yarns is very costly while the time consumed in the cutting of the yarn ends is very significant.
It has been recognized that it would be advantageous to be able to reduce the yarn waste by cutting and clamping the pattern yarns at certain areas during the knitting cycle. For example, U.S. Pat. Nos. 2,893,229 and 3,016,725 disclose cutting and clamping devices particularly adapted for use with Banner Model SCP and SCOP machines in which two diametrically opposed yarn feeding and knitting stations are provided. However, the cutting and clamping devices of these two patents are adapted to operate only one time during the knitting of each sock, that is, upon completion of the knitting of the pattern in the leg of the sock so that the cordlike bundle of pattern yarns does not extend through the rotary knit foot portion. This results in some yarn savings but does not provide for the individual cutting and clamping of each pattern yarn as it is moved into and out of active yarn feeding position during the knitting of the pattern in the leg.
U.S. Pat. Nos. 2,924,958 and 3,271,979 disclose yarn cutting and clamping devices particularly adapted for use with a solid color pattern hosiery knitting machine of the type manufactured by Textile Machine Works and known as a CKA machine which is provided with four spaced-apart yarn feeding and knitting stations. These patents disclose the use of a more or less conventional scissors type of yarn cutting and clamping device positioned adjacent each yarn feeding and knitting station. The individual yarn cutting and clamping devices are operated by solenoids in U.S. Pat. No. 2,924,958 while they are operated by a separate control pattern drum in U.S. Pat. No. 3,271,979. The cutting devices of these two patents are expensive to install on the knitting machine and occasionally permit one of the clamped multiple yarns to be released from the clamping device and cause the formation of a defective sock. Because of the deficiencies of these prior types of known cutters and clamps for this particular type of solid color hosiery knitting machine, none of the prior devices have been widely used on this type of knitting machine.